Checking if a variable is of data type double

Question

I need to check if a variable I have is of the data type double. This is what I tried:

try
{
    double price = Convert.ToDouble(txtPrice.Text);
}
catch (FormatException)
{
    MessageBox.Show("Product price is not a valid price", "Product price error", MessageBoxButtons.OK, MessageBoxIcon.Error);
    return false;
}

I thought this would work, but obviously, I failed to realize if txtPrice.Text had anything other than a number in it, the Convert class will just parse it out.

How can I realiably check if a variable is a double?

Answer 1

Use this:

double price;
bool isDouble = Double.TryParse(txtPrice.Text, out price);
if(isDouble) {
  // double here
}

Answer 2

Couldn't you just use:

double.Parse(txtPrice.Text);

?

With this you will a FormatException saying "Input string was not in a correct format." if the string value isn't a double, which looks to be roughly what you were doing manually anyway.